Apparatus for drying continuous lengths of film or paper or the like



March 1, 1966 H. w. SACHS 3,237,316

APPARATUS FOR DRYING CONTINUOUS LENGTHS 0F FILM OR PAPER OR THE LIKE Flled Sept. 28. 1962 3 Sheets-Sheet 1 INVENTOR.

HANS W. SACHS A TTORNEY/ March 1, 1966 H. w. SACHS 3,237,316

APPARATUS FOR DRYING CONTINUOUS LENGTHS OF FILM OR PAPER OR THE LIKE Flled Sept. 28, 1962 3 Sheets-Sheet 2 INVENTOR HANS W. SACHS M W, m w 2% A TTORNEYS March 1, 1966 H. w. SACHS 3,237,316

APPARATUS FOR DRYING CONTINUOUS LENGTHS OF FILM OR PAPER OR THE LIKE Filed Sept. 28, 1962 3 Sheets-Sheet 5 FIGIG FIGIZ IN VENTOR.

HANS W. SACHS A TTORNEYS United States Patent 3,237,316 APPARATUS FOR DRYING CONTINUOUS LENGTHS 0F FILM 0R PAPER OR THE LIKE Hans W. Sachs, 29 Virginia Ave., Binghamton, N.Y. Filed Sept. 28, 1962, Ser. No. 226,794 Claims. (Cl. 34115) This invention relates to improvements in drying apparatus, and more particularly, relates to a dryer for impin-gement drying of a web or web coating, with the web being held by its edges and passed in a serpentine path during the drying operation.

In the drying art, machines have been constructed for the drying of a coating on the surface or paper and machines have been constructed for drying of a coating on the surface of film. While it is generally understood in the art that contact with the coated surface of a web, while the coating is still wet, soft or tacky, must be prevented in order to avoid damage to the coating, there are applications in which frequent contact with the uncoated side of the web, such as contact with supporting rollers, is also liable to lead to objectionable flaws on the uncoated side of the Web. A specific example is the drying of freshly coated photographic film. A film base web has high tensile strength and tear strength and moderate expansion and contraction under drying conditions, but it also must be scrupulously protected against scratches and abrasions on the uncoated as well as on the coated side. In order to avoid frequent contact with rollers, film dryers have been designed in the prior art to carry and transport the web by means of grippers which, somewhat in the manner of a tenter frame but with substantially greater spacing between gripping elements, hold the web merely by its edges. Paper webs particularly when wet, would not have suflicient tensile and shear strength to be held in this manner without tearing and, while grippers for film having fixed lateral spacing have been used with success, the very substantial amount of expansion and contraction paper will display under drying conditions, will not permit the use of grippers with fixed lateral spacing for paper. Paper dryers which carry the web on rollers or bars, take advantage of the papers insensitivity to scratches, and use these supports to avoid stresses and provide for dimensional changes during drying. However, paper web dryers of this type would not be satisfactory for use in drying a coating on a film web as the uncoated side of the film would suffer abrasions from the frequent contact with rollers. In addition, the length of paper dryers with roller support as frequently used in prior art, is very uneconomical in respect to .the building space required.

It is therefore an object of this invention to provide a dryer which can handle both film and paper, under con ditions very suitable for both, without shortcomings in the way of causing scratches and abrasions, and without placing excessive stresses on the web edges, and without re strictions due to air blast (used in the prior art in various forms to support the web) effects on the web of known prior art dryers.

In an impingement dryer, the space taken up by the dryer is quite important. In other words, space economy is of great importance. This invention provides an impingement dryer having good space economy for the handling of webs with a coating to be dryed by air impingement.

Due to the possibilities of dimensional changes under drying conditions and different materials handled, it is highly desirable that a dryer be flexible and adjustable to accommodate such changes and dimensions without creating undue tension on the web. This invention provides a film dryer which may accommodate changes in the diice mensions of the web being dried both longitudinally and laterally while gripping the edges of the web.

It is desirable in an impingement dryer, to have lightweight moving elements which lack criticality in their radial movements. It is also desirable to hold the film firmly but with holding means which are sufficiently flexible to permit adjustments for accommodating dimensional changes in the web during drying. This is accomplished in the subject invention by lightweight wheel cages having rims for supporting edge belts which hold the web by its edge only. Lateral changes in web dimensions can be accommodated by adjustable spacing of the rims of the wheel cages.

In impingement dryers, the air supplied for drying a coating on a web should not interfere with the return air and should be applied as closely as possible to the web. This is accomplished in the subject invention by a unique air supply and return system.

A moving web dryer of substantial length must cornpensate for longitudinal expansion and contraction of the web during drying. In this invention articulated or zoned drives of edge gripping belts accommodate longitudinal changes in web dimensions; i.e., the dryer is subdivided into sect-ions which can be driven at different and varying speeds.

For the threading of a web through a dryer with zoned sections ordinarily manual operation would be required for threading between each of the sections. By a sel'fthreading arrangement as disclosed in the subject invention, this manual operation may be dispensed with.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose by way of example, the principle of the invention and the best mode which has been contemplated of applying that principle.

In the drawings:

FIG. 1 is a somewhat schematic side elevation view of the air impingement serpentine dryer of this invention showing an articulated or zoned drive of web edge holding belts;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 showing in more detail, impingement supply and wheel cage assemblies;

FIG. 3 is a detailed showing of mounting of a wheel cage;

FIG. 4 is an enlarged detail of phantom circled area 4 in FIG. 2 showing a web held between edge belts on an upper wheel cage;

FIG. 5 is an enlarged detail of the phantom circled area 5 in FIG. 2 showing the web being held by edge belts on a bottom wheel cage;

FIG. 6 is a perspective view of a self-threading attachment mule bar for the leading end of a web to be dried;

FIG. 7 is a schematic side elevation of a portion of the dryer showing attachment of the self-threading mule bar and the starting of the web through the dryer;

FIG. 8 is a schematic side elevation view showing the self-threading attachment and the operation thereof between articulated or zoned areas in the edge belt drive;

FIG. 9 is a side elevation view of a modification in the edge belt drive showing a single edge belt pair drive for both top and bottom wheel cage assemblies;

FIG. 10 is a detailed sectional view taken along line 10-10 of FIG. 9 showing gripping of the web by a single edge belt and a wheel cage rim;

FIG. 11 is a schematic side elevation view of another embodiment using one pair of edge belts around the upper and lower wheel cage assemblies and another pair of edge belts around the lower wheel cage assemblies only;

FIG. 12 is a detailed sectional view taken along line 1212 of FIG. 11;

FIG. 13 is a sectional elevation View of a modification and improvement in the air supply and return assembly;

FIG. 14 is a sectional view taken along line 1414 of FIG. 13;

FIG. 15 is a detail view of a portion of the air supply assembly showing an alternate nozzle shape;

FIG. 16 is a fragmentary enlarged side elevation of phantom circled portion 16 of FIG. 1 illustrating the support of the edge belts between the wheel assemblies.

In general, this invention provides for drying a moving web which may be sensitive to abrasions, such as film, or which may have little strength and relatively large dimensional changes during drying, such as paper, by means of air impingement on a coating of the web while the web is traveling in a sepentine path around the periphery of a plurality of closely spaced wheel cages. The wheel cages have rims supported by spokes and the edges of the web being dried are held and guided by edge belts trained around the rims of the wheel cages. Air supply means are provided for directing a supply of drying air to one side of the web and the construction of the wheel cages as well as a zoned drive of the belts provides for both longitudinal or lateral dimensional changes of the web being dried. In addition, a self-threading attachment for an articulated drive is shown as are certain improvements in supplying the impinging drying air. The web is gripped by two belts at its edges trained around the rims of the wheel cages in the preferred embodiment, and other embodiments are shown in which only a single gripping belt is used in combination with a portion of the wheel cage rim, and a single gripping belt is used on one set of wheel cages while two gripping belts are used on the other of the set of wheel cages.

Referring now to the drawings, a web W coated except along its edges is moved in the direction of the arrows, FIG. 1, and is dried in an air impingement serpentine dryer 10. The serpentine dryer 10 includes a plurality of the substantially identical wheel cage assemblies including upper wheel cage assemblies 12, 12, 12, etc., and lower wheel cage assemblies 14, 14, 14, etc. The wheel cage assemblies are positioned as shown in FIG. 1 so that the web W travels in a serpentine path coincident with the periphery of the cages.

Air for drying a coating on the web is supplied from an air supply distributor assembly 16 through air supply openings 18 therein and is directed onto one surface of the web.

The edges of the web being dried are gripped by upper and lower edge belts trained over rims on the periphery of the wheel cages and gripping each edge of the web. A top edge belt 20 and a bottom edge belt 22 are provided for this purpose, as shown in the left-hand side of FIG. 1. Edge belt 20 is guided over a plurality of guide rollers 24, 24, etc., and over a tension regulating roller 26 resiliently supported by a spring 27 to provide the requisite tension in the edge belt 20. Similarly, edge belt 22 is guided over a plurality of guide rollers 28, 28, etc., and over a tension regulating roller 30 supported from a spring 31 for a similar purpose.

To accommodate longitudinal changes in web dimensions during drying, the drive belts may be zoned or articulated. By employing a sensing element on or at the web which is sensitive to variations in tension, the drives for the belts may be placed under automatic control so that the speed is varied in accordance with dimensional web changes. Zoning also serves to keep the length of the belts within reason and reduces the amount of takeup required. Articulation is shown, for example, in the center portion of FIG. 1. At a zoning point, near the center of FIG. 1, the web W passes from an upper wheel cage 12a to a lower wheel cage 14aand on the lower wheel cage 14a the web W is guided by means of another set of edge belts including upper edge belts 34 and lower edge belts 32. Edge belts 20 must travel at the same speed as edge belts 22, and similarly edge belts 32 must travel at the same speed as edge belts 22, and similarly edge belts 32 must travel at the same speed as edge belts 34. The two sets of edge belts 20, 22 and 32, 34 may be driven at different and varying speeds, and automatic controls may be provided therefor. Although only one zoning point is shown the dryer may have as many zones or articulations as called for by the dimensional changes of the web and the length of the dryer.

The web may be guided into the dryer from flanged guide roller 36, the flanges on roller 36 serving to align the web with the edge belts. Also, roller 36 may have a convex (crown) or concave periphery which will cause the web to form a lateral slack as its edges enter between the belts. This arrangement reduces the amount of lateral spacing adjustment required of the Wheels, as the web shrinks during drying, and makes lateral adjustment less critical. The web may be removed from the dryer by geared roller cluster 38 after it is dry. The peripheries of the rollers in the cluster 38 do not touch and they may be driven by a torque motor (not shown).

At the point where both edge belts are not supported by the rims of the wheels cages, the web W is held between the belts and during this transfer from one cage to another, the gripping force of the belts is reduced at the tangential transfer locations. As shown in the detail in FIG. 16, the belts 32, 34 are contacted and further held together by a plurality of support rollers 35, 37 hearing on the belts but not on the web. The support rollers are carried by and rotatable in plates 39, one of which may be fixed while the other may be urged against the fixed plate by means of springs 41. The force supplied by the sup port rollers guides the web edges between the transfer points. Since the blast of air from air supply openings would develop a force which may cause the edges of the web to slip from between the edge belts, no air supply openings are located at these transfer points. Inasmuch as the web travel path at the transfer points approaches the vertical, gravity forces tending to pull the web edges from between the edge belts are very minor.

Reference may be had to FIG. 2 for a transverse sectional view through the dryer showing an upper wheel cage assembly 12 and a lower wheel cage assembly 14. The air supply distributor assembly 16 contains the drying air which is forced out openings 18 and this drying air may be returned within a casing 40; the area within casing 40 serves as a return air plenum and can be suitably zoned by partitions, for example at the drive articulation. The air supply distributor 16 may also be zoned the same as return casing 40, for instance at the drive articulation points. For upper wheel cages 12 air flow is directed from above and flows out the sides as shown in FIG. 2. For lower wheel cages 14 the air supply distributor 16 is within the cage between the spokes 42, and the air returns between the spokes 42 as shown.

As can be seen, the web W is supported by edge gripping belts 20 and 22 which grip the edge thereof and hold the same while being guided by a rim of the wheel cage assemblies 12 and 14. More particularly, wheel cages 12 and 14 include a plurality of spokes 42 emanating from hubs 44. Rigidly secured to the periphery of the spokes 42 are grooved rims 46 for supporting the edge belts 20 and 22.

Suitable rigid supports 48 support each of the wheel cage assemblies in the dryer from a base or the like (not shown). The supports 48 journal a spindle shaft 50 which is only rotatable for lateral adjustment of the rims 46 toward and away from one another. Referring to FIG. 3, hubs 44 are held rotationally to hollow shaft 54 but can slide longitudinally on keys 52 and shaft 54 which in turn is rotatably journalled on the spindle shaft 50. Shouldered bushings 56 rotatably support each end of the hollow shaft 54 and they are pinned to the spindle shaft 50; shoulders 57 of bushings 56 prevent axial Shii e ing of hollow shaft 54.

Rigidly attached to each hub 44, is a Z shaped connecting ring 58 which rotates with the wheel cage assembly. Contacting the outer end of the Z shaped connecting ring is a nut 60 and flange 62, the Z shaped connecting ring rotating in the space between the flange on nut 60 and the flange 62. The nut 60 is threaded on support spindle shaft 50 and is prevented from rotating relative to the support 48 by means of a pin 64. The shaft 50 is provided at opposite ends with right and left hand threads for accommodating correspondingly threads nuts 60, 60. To prevent axial shifting of shaft 50 pin collars 67 are secured to each end of shaft 50 with the inside of the collars bearing on the outside of supports 48.

One end of the spindle shaft 50 is provided with a self locking worm gear 66 meshing with a drive worm 68 driven by a suitable motor 70. It can be seen that rotation of spindle shaft 50 causes the nuts 60, 60 to both move inward or outward depending on the action of rotation and this accordingly varies the distance the rims 46 are apart from one another and this adjustment is provided to accommodate for lateral changes in web dimensions. Automatic sensing equipment (not shown) may be provided for controlling motor 70 to provide automatic spacing picked up from the prevailing web Width within any section of the dryer. Alternatively, manual shaft drive may be used for controlling the lateral spacing of the web support rims.

The drive for each interconnected group of wheel cage assemblies could be applied to disc 72 of one of the wheel cages and, by means of edge belts 20 and 22, the driving force would be transmitted to the other wheel cages in that group. Alternately, the drive could be applied to edge belts 20 and 22 which in turn would drive the wheel cages. Further, since the wheel assemblies turn freely and are not likely to load the belts sufficiently for adequate grip tension, the disc 72 can be employed, by means of brake bands or brake shoes bearing on the rim surface of discs 72, as drag brakes thereby increasing the tension in the edge belts which hold the web and also rotate the wheel cages. The drag brakes increase the tension in the belts and, in turn, increase the gripping force with which the edges of the web are held between the edge belts.

FIG. 4 shows in detail the gripping of an edge of Web W by the edge belts 20 and 22. The edge belts have a distinctive configuration to grip the web and may be constructed of a rubberized fabric with wire reinforcement. The belts must have sufficient stiffness for firm gripping action, but also must have sufficient elasticity to permit flexing and curving in two opposite directions. For a pair of belts riding on top of each other and around successive wheel rims while being flexed successively in alternate directions, the outer belt in each case will be subjected to stretching and the inner belt will be compressed while the line in which the belts contact each other and hold the web, will be in or near the neutral zone in which neither stretch nor compressions occurs. In order to minimize stresses acting on the belts, their thickness should be the minimum compatible with adequate strength and gripping action on the Web, and the wheel cage diameters should be as large as possible in relation to the thickness of the belts; also, the wire reinforcement inside the belts should be in or as close as possible to the neutral zone, as shown in FIGURES 4, 5, 10, and 12. The belt 20 may be constructed with a pair of longitudinal projections 74 and a corrugated longitudinal area 76. Similarly, belt 22 may have a longitudinal depression 80 mating with longitudinal projection 74 and a corrugated area 78 corresponding to corrugated area 76 for gripping the web therebetween. The belt 22 may have a wide longitudinal projection 84 which corresponds to a wide groove 82 in rim 46 of wheel cage 12. As can be seen in FIG. 4, the upper belt 20 is on top at the upper wheel cage assembly 12.

Referring to FIG. 5, at the lower wheel cage assembly 14, the belt 20 is adjacent the wheel cage and fits into a narrower groove 86 in rim 46. However, the web W is still gripped between the two corrugated areas 76 and 78 of the belts 20 and 22 as shown. The corrugations are of such a shape and dimension as to effect a tight grip on the web without objectional distortion or cutting of the web. For use with drying film, the film edges could be pre-embossed to further improve the grip.

FIGS. 6, 7 and 8 show a self-threading attachment and the operation thereof in guiding a web end through the drive articulation zone. A mule bar which may be made of plastic is attached to the leading edge of web W by any suitable means when the web is to be started through the dryer as shown in FIG. 7. The mule bar 90 has reduced thickness ends 91 for gripping by the edge belts. FIG. 8 shOWS the mule bar 90 as it is traveling and leading the web through the drive articulation zone. After leaving wheel cage 12a the ends 91 of the bar 90 come to rest on belt 34 and the mule bar is carried along to the nip of belts 34 and 32. This eliminates manually threading the web through the drive articulation zone.

Referring to FIG. 9, a modification of this invention may be provided with a single pair of edge belts for gripping the edges of the web and holding the edges against the rims of a wheel cage assembly, and an articulated drive arrangement may be provided therefor. As shown in FIG. 9, edge belt 92 may be trained around one of a series of upper wheel cages 12 and around suitable guide rollers 93. Similarly, a belt 94 may be trained around lower wheel assemblies 14 and around guide rollers 95. At an articulation point as illustrated in FIG. 9, another upper edge belt 98 may be carried around upper wheel assemblies 12 and guide rollers 99, while another lower edge belt 96 may be provided around lower wheel cages 14 and guide rollers 97.

FIG. 10 shows a configuration of a T-belt 92 such as used with the FIG. 9 embodiment. The T-belt 92 has one longitudinally extending projection 101 and a longitudinally corrugated section 100 for gripping the edge of a web W against a correspondingly corrugated portion 103 of rim 46 of wheel assembly 12. Thus, the web W will be held between the corrugations 100 of the belt 92 and the corrugations 103 of the rim 46 while the projection 101 is guided in groove 102 of the wheel cage rim 46.

FIG. 11 shows a further modification in which a double T-belt is used and trained around the periphery of both upper and lower wheel cages while an extra T- belt is trained around the lower wheel cages only. As shown in FIG. 11, a double T-belt 104 is trained around both the lower wheel cage assemblies 14 and the upper wheel cages 12, while a further belt 106 guided by guide rollers 107 is trained around the periphery of only the lower wheel cage assemblies 14.

As shown in FIG. 12, the upper belt 104 is similar in shape to belt 20, while the wheel cage rim 46 has corrugations 103 therein, so that the belt 104 holds the web W against the corrugations to hold the web tightly at its edges. The section taken along line 12a12a is identical to FIG. 5 in that the lower wheel cage assemblies 14 have an additional edge belt 106 identical in shape to belt 22 provided with corrugations for holding the edge of the web therebetween.

FIGS. 13, 14 and 15 show a modification of the air supply and air return system. An air supply plenum 110 is provided with a plurality of extending nozzles 112, which extend down to practically adjacent the web W to protect the air supply stream against diversion and disturbance by return air flow. With the nozzles 112 extending adjacent the plane of the web, the drying air flow is as shown in FIGS. 13 and 14. The space enclosed by nozzles 112, bottom of supply air distributor 110 and the web, serves as a channel guiding the return air to the edges of the web. The return air flow to return header 116 through opening 118 shown in FIGS. 13 and 14 does not affect the flow of the supply air for drying and the nozzles 112 promote an intimate contact of the air with the web, thereby promoting drying efiiciency and air economy. Return air header 116 may be below the web as shown, or may be at the side of the web as illustrated in FIG. 2.

Also as shown in FIG. 15, a modified nozzle construction with nozzle 120 can be used in place of the nozzles 112 in FIGS. 13 and 14. The nozzle restriction is adjacent the plenum 110 and the air flow diverges therefrom while being guided by the nozzle side walls.

While there have been shown and described and pointed out fundamental novel features of the invention as applied to the preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

I claim:

1. A web drying apparatus comprising in combination;

(a) a plurality of rotatable wheel cages including spaced open cages having parallel rims,

(b) means for mounting the wheel cages adjacent one another in parallel rows and training a web around the periphery thereof in a serpentine path,

(c) at least one pair of edge'belts cooperating with the opposite rims of all the wheel cages of at least one row and opposite edges of a web to hold and support the opposite edges of the web, the belts being trained around the rims of the wheel cages in a serpentine path, and

(d) an air supplying means for directing drying air on to one surface of the web while the web is traveling in the serpentine path with the web edges held by the belts supported by the spaced parallel rims of the wheel cages, the air supplying means being located at least partially within some of the wheel cages.

2. An apparatus for drying a moving web, comprising a plurality of wheels mounted side by side and staggered in two rows such that the web may be trained substantially in the plane of the periphery of the wheels in a serpentine path, and means for directing impinging air for drying on to a surface of the web, the wheels being open cages including a pair of spaced parallel rims for supporting opposite edges only of the web, at least one pair of edge belts trained around the rims of the wheels in a serpentine path and contacting and holding both edges of the Web while supported on the rims of the Wheel cages as drying air is directed against the Web for accomplishing the drying of the same.

3. An apparatus as defined in claim 2, wherein there are two pairs of edge belts trained around the periphery of the rims and holding the Web edges therebetween the belts including means extending longitudinally thereof and co operating with each other and with the rims of the wheel to prevent lateral slippage of the belts.

4. An apparatus as defined in claim 2, wherein there is a single edge belt holding the web against the rim of the wheel cages the belt including means extending longitudinally thereof to engage the rim of the wheel cage and prevent lateral shifting.

5. An apparatus as defined in claim 2, further com-prising corrugations in the holding edges of the web engaging side of the edge belts.

6. An apparatus as defined in claim 2, further comprising air supply means for one side of the web, including a plurality of nozzles and an air supply plenum chamber, the nozzles extending from the plenum chamber to a point adjacent the surface of the web so that the air supplied thereby is not afiected by air return.

7. An apparatus as defined in claim 2, further comprising mechanical means for adjusting the lateral spac ing between the rims on a central support shaft of the wheel cages.

8. An apparatus as defined in claim 2, further comprising means for supporting the edge belts in the space between adjacent wheel cages.

9. An apparatus as defined in claim 2, wherein the drive of the edge belts is zoned for adjustment of the speed of driving.

10. An apparatus as defined in claim 2, further including an attachment bar for securing to a leading edge of the web for automated threading of the web through the point of drive belt zoning.

References Cited by the Examiner UNITED STATES PATENTS 1,552,099 9/1925 Walsh I- 3423 2,061,976 11/1936 Merckens 34115 2,211,332 8/1940 Jones 34-117 2,823,467 2/1958 Minami 34155 2,861,508 11/1958 Baumbach 34--155 3,046,771 7/1962 Bailey 34-123 3,060,594 10/1962 Meier-Windhorst 34158 References Cited by the Applicant UNITED STATES PATENTS 1,032,713 1912 Sowden. 1,122,282 1914 Kilberry. 1,555,957 1925 De Ybarrondo. 1,726,134 1929 Alexander. 2,054,391 1936 Schmidt. 2,091,805 1937 Chuse. 2,308,161 1943 Eckstein et al. 3,019,855 1962 Engle.

WILLIAM F. ODEA, Primary Examiner.

NORMAN YUDKOFF, Examiner. 

1. A WEB DRYING APPARATUS COMPRISING IN COMBINATION; (A) A PLURALITY OF ROTATABLE WHEEL CAGES INCLUDING SPACED OPEN CAGES HAVING PARALLEL RIMS, (B) MEANS FOR MOUNTING THE WHEEL CAGES ADJACENT ONE ANOTHER IN PARALLEL ROWS AND TRAINING A WEB AROUND THE PERIPHERY THEREOF IN A SERPENTINE PATH, (C) AT LEAST ONE PAIR OF EDGE BELTS COOPERATING WITH THE OPPOSITE RIMS OF ALL THE WHEEL CAGES OF AT LEAST ONE ROW AND OPPOSITE EDGES OF A WEB TO HOLD AND SUPPORT THE OPPOSITE EDGES OF THE WBE, THE BELTS BEING TRAINED AROUND THE RIMS OF THE WHEEL CAGES IN A SERPENTINE PATH, AND (D) AN AIR SUPPLYING MEANS FOR DIRECTING DRYING AIR ON TO ONE SURFACE OF THE WEB WHILE THE WEB IS TRAVELING IN THE SERPENTINE PATH WITH THE WEB EDGES HELD BY THE BELTS SUPPORTED BY THE SPACED PARALLEL RIMS OF THE WHEEL CAGES, THE AIR SUPPLYING MEANS BEING LOCATED AT LEAST PARTIALLY WITHIN SOME OF THE WHEEL CAGES. 